Powder impermeable to liquids



'- Patented Sept. 8, 1925.

UNITED STATES 1,552,871 PATENT err-"ice.

3mm orrnnnizriu, or LEVALLOIS-PERRET, FRANCE, ASSIGNOR TO socm'rr. ANONYME LE cannons, orLnvnLnoIs-rmmn'r, runner.

POWDER mrmmnnnm 'ro mourns.

No Drawing. Original application filed April 10, 1924, Serial No. 705,684. Divided and this application filed February 18, 1925. Serial No. 10,147.

v To allwhom it may concern:

Be it known that I, Rum: OPPENnEIM, a citizen of France, residing at Levallois- Perret, Seine, France, have invented certain 5 new and useful .Improvements in Powders Impermeable to Liquids, of which the following is a specification. I

The present application is a division of my application No. 705,684, filed April 10,

' 1924:, and the invention relates to a powder consisting of porous particles, which has been rendered impermeable to liquids by the process set forth in said application. -The powder forming the subject-matter of the present application retains its propert es for use as a catalysis and for the absorptlon of liquids duringlong'er periods of use.

The process set forth in my said application No. 705,684 is particularly applicable to the impermeabilization of the grains of powder which consist of porous particles, such as powdered wood charcoal, utilized either in an ag lomerated state or 111 a pulverulent state, 1n electric batteries or accu- ,mulators, for the purpose of absorbing the gases evolved by the reactions which take place and to permit the depolarization by the oxygen of the air. By the application of this process the grains of powder forming the subject-matter of the present invention, cannot be penetrated by the liquid of the electrolyte, yet the gases evolved during .the working of.the battery may readily pass through the same. 4 The present invention affords the advanta es of ensuring to electric batteries, which po arization is performed by, air and absorption of the gases evolved by the reaction which takes place, a satisfactory normal 40 working for a longer period of time and to considerably reduce their internal resistance I to the passage ofthe current.

The process for forming the new powder consists particularly, in intimately mixing with the powder, a colloidal suspension capable of pectinization, in a quantity sufficient to coat each individual ain of the powder with a pectinized film, impenetrable by liquids but yet permeableto ionized gases. The powder with the impermeabilized porous grains thus obtained may afterwards be utilized either alone or admixed with a depolarizer', such as manganese dioxide, for

example. This powder will be enclosed in a porous receptacle of earthenware or fabric, or will be compressed into the form of briquettes.

By way of explanation, I will proceed to describe a mode of application for producing the impermeabilization of a wood charcoal powder designed to be used in the manufacture of electric batteries, in which 'depolarization is performed by the oxygen of the air.

Into a vessel containing about 30 kilogrammes of ordinary wood charcoal, in powdered form, to which powdered graphite may be added for the purpose of increasing its conductivity, there is poured a colloidal suspension, prepared for example, in the following manner :v

87 5 grammes of fecula are dissolved in 1 litre of cold water and this solution is after:

wards mixed vn'th about 9 litres of water V heated to a temperature of about C.

After it has cooled down, this colloidal suspension is poured over the powdered wood charcoal, to which powdered graphite may or may not have been added, and the whole mass is stirred so as to obtain as intimate a mixture as possible.

During this stirring, the colloidal suspension forms-on the surface of each grain of t, e

owdered wood charcoal, a coagulum A whic dries until pectinization takes place.

' Each grain of the powder forming the subject-matter of the present application, is therefore enveloped by this pectinized coagulum, which constitutes a film-like coat ing functioning to protect it against any ulterior penetration y liquids.

pidity with which the coagulum is formed and its immediate pectinization, each porous grain is immediately isolated from the colloidal sus ension, and the duration of the It should be noted that owing to the rastirrin o the powder with this latter has no in uence on the thickness of the film formed on each grain. Only an extremely thin film-like coverin can therefore form with any penetration o the colloidal material into the mass of each of the porous grains, and consequently theselatter alwa s retain their properties of absorption an adsorption of the gases.

The product thus obtained (the grains of which are now impermeabilized) can be used either in dry batteries or those in which .the liquid is stationary, and even in accumulators. It may be used with or without manganese dioxide, either in the form of powder or in an agglomerated form according to the type of battery or accumulator with which it is to be employed. In the latter case, the powder is rammed around the positive electrode of the bat- .tery, into a porous vessel of earthenware of the ordinary kind or into a fabric receptacle, and in the second case th powder is compressed into the form of blocks or briquettes agglomerated onto the positive electrode of the battery or affixed thereto by any well known means.

For the constitution of the colloidal suspension utilized in the process of forming When fecula is used I may add thereto acertain proportion of gelatin, for example to grammes per litr of suspension, for the purpose of retarding the pectinization, and to eliminate cracks in the pectinized colloid, particularly in cases where the latter is to be agglomerated under severe compression.

, The proportions of the elements employed in the process for formingthe improvedpowder may be modified according to the applications thereof.

Claims:

1. A powder consisting of porous grains enveloped by pectinized coagulum forming a film-like coating on the grains and protecting the same against any ulterior penetration by liquid, while permitting any free penetration by gases.

2. A powder of porous grains of charcoal, each enveloped by pectinized coagulum forming a film-like coating to protect it against any ulterior penetration by liquid.

3. As a new article of manufacture, a

pulverulent mixture of powdered charcoal and" graphite, the grains of the powdered charcoal each being enveloped by pectinized coagulum forming a film-like coating to protect (ilt against any ulterior penetration by li ui 4. As a new article of manufacture, pulverulent material consisting of a mixture of powdered charcoal, graphite and manganese dioxide, the grains of the pulverulent mixture being enveloped by pectinized coagulum forming a film-like coating toprotect them against any ulterior penetration by liquid.

5. The new product constituted by a powder composed of porous grains rendered impermeable by mixing the same with a colloidal suspension capable of pectinization, in such a way that each of the grains of this powder is covered individually with a pec-' tinized film impenetrable by liquids.

In testimony whereof I hereunto afiix my 75 signature. RENE OPPENHEIM. 

